In Georg Wilhelm Freidrich Hegel's philosophy of "absolute idealism," reality is broken down by our distinction between it and our knowledge of it, and the understanding of reality is the understanding of our own concepts, and vice versa. .
Often defined as justified true belief--though just as often disputed as replacing, not involving, belief--knowledge is the familiarity, awareness, or understanding gained through study, discovery, or experience. Knowledge is often judged in empirical, a priori, or a posteriori terms, especially in logical positivism. Some have contrasted the differences in moral and factual knowledge, i.e., knowing how to perform a musical piece and knowing that the musical piece was written for a particular instrument. Knowledge is quite often attached to the connotations of scientific reasoning, quantitative and qualitative data, rationalism, deduction, and induction. Belief, however, is an agreement to, acceptance of, or conviction in the truth, actuality, or validity something. As mentioned above, belief is in contrast with knowledge, as one states a belief when unjustified in claiming knowledge.
Though defined as the conformity to fact or actuality, the meaning of truth has been a debatable topic for eons, as the question as to what constitutes truth has been handed down from ancient Greeks to contemporary philosophers. Truth has been argued to be subjective as opposed to objective, been fought for between absolutism and relativism, and has been battled over by a priori reasoning versus the factually oriented rationalism and empiricism. Truth has been analyzed in terms of the relationships between propositions and other things, i.e., the tautology-inclined correspondence theory, and the coherence and pragmatic theories, both containing characteristics of relativism.
Psychology uses the term "cognition" as a generality to cover the functions involved in processing and synthesizing information.
